How to Merge All Photo Libraries (including iPhoto Libraries into "One Photos System Library"?

You can not exactly

If you migrate all libraries to Photos and then you have two options

1 - upload each one successively to iCloud Photos library which will merge them except for faces and projects

2 - purchase PowerPhotosand use its merge command to merge one version of the photos

LN

If you own Aperture 3.6, you can merge your iPhoto Libraries using Aperture. This will be lossless - see this help page: Aperture 3.3: How to use Aperture to merge iPhoto libraries - Apple Support

The two options Larry mentioned, have different drawbacks:

• Merging in iCloud will give the best results, because it will preserve the originals and edited versions as pairs, and you will be able to undo your edits. But it requires to purchase an iCloud storage plan with enough storage allowance to keep all photos in iCloud.
• Merging with PowerPhotos requires the full version of Power Photos, and you can only import the originals or the edited versions, but not both as a pair. See this Help Page: https://www.fatcatsoftware.com/powerphotos/Help/merging%20libraries.html

None of the two merging options will preserve the projects (Books, calendars, slideshows) and neither the faces. So keep a backup of the original libraries.

See more in this user tip: Notes on Merging Photos Libraries

Hi Léonie, thanks for the very helpful post Notes on Merging Photos Libraries. I have a question about that article, but I can't seem to reply to the original post. Could you give a little more explanation on the final step: • Now enable the larger library as your iCloud Photo Library.

What is the best way to accomplish this part of the merge? Holding down option key on Photos startup and choosing to open the other library? (in my case, an iPhoto library from a former computer) Do I have to take any other action to "enable the larger library as my iCloud Photo Library"?

Thanks!

What is the best way to accomplish this part of the merge? Holding down option key on Photos startup and choosing to open the other library? (in my case, an iPhoto library from a former computer) Do I have to take any other action to "enable the larger library as my iCloud Photo Library"?

You can only enable the system Photo Library as your iCloud Photo Library.

• To switch to a different Photos Library you can simply double click the library in the Finder and Photos will show a prompt, if you want to open this library. Or hold down the options key while launching Photos. Or drag the library onto the Photos icon in the Dock. Any Photos library needs to be on a drive formatted to MacOS Extended (Journaled), if you want to open it in Photos and the drive needs to be directly connected, not using a network connection.
• Once Photos has been launched, make it the System Photos Library in the Photos > Preferences > General. "Use as System Photo Library" needs to be grayed out. Then enable iClod Photos Library in the Photos > Preferences > General.

Ciao Léonie,

i have some issues in merging 2 photos libraries. I was reading your notes but it doesn't help. Situation is as follows:

1 photos library is on my iMac

1 photos library is on my MacBook Air

Both are activated for icloud storage.

Do you have any idea what I can do?

Thanks a lot!

Ralph

Both are activated for icloud storage.

If both libraries on both Macs are syncing with iCloud Photo Library, bot libraries should be identical. Does that not happen?

Actually yes in the sense that all future items are there on both computers. But the past is not equal...

You're super fast! thanks a lot!

Check both libraries if the past photos are items that cannot upload to icLoud Photo Library. Create a smart album in both libraries with the two rules:

• Photo is unable to upload to iCloud Photo LIbrary
• Photo is referenced

Combine these rules with "Match any of the following conditions"

Are these smart albums empty?

nope. One contains almost 10.000 items. But now I get another clue: some (if not all) items are stored on an external drive which is currently not connected with the laptop of the 10k items...

Could it be because of this? And if so, what do I need to do to upload them into iCloud?

One contains almost 10.000 items. But now I get another clue: some (if not all) items are stored on an external drive which is currently not connected with the laptop of the 10k items...

If the photos are referenced outside the Photos Library, they cannot upload to iCloud at all. If you want the photos in iCloud, you have to consolidate them into your Photos Library , so Photos can manage them.

And that means your Photos Library needs to be on a drive with enough free storage to hold all your photos.

Or, if you want to keep the Photos Library on your system drive, use "Optimize Storage". Than you could consolidate your 10000 photos into the library and wait for iCloud to optimize the photos. You could move them into the the library with "File > Consolidate", but not all at once. DO it slowly and iCloud time to optimize the storage.